1. Field of the Invention
The present invention relates to an electrode assembly, as well as a battery cell, a battery pack, and a device including the electrode assembly, and more particularly, to an electrode assembly formed by stacking at least two unit cells having different sizes to form a stepped portion on the electrode assembly, and a battery cell, a battery pack, and a device including the electrode assembly.
2. Description of the Related Art
Demand for secondary batteries has markedly increased with the development and increasing usage of mobile devices, and particularly, lithium secondary batteries are widely being used as power sources in various electronic products such as mobile devices, owing to the high energy density, high operating voltages, easy-to-store characteristics, and relatively long lifespan thereof.
Generally, lithium secondary batteries are formed by disposing an electrode assembly and an electrolyte within a battery case and sealing the battery case. Lithium secondary batteries may be classified into cylindrical, prismatic, and pouch type batteries, according to the shape thereof, and lithium ion batteries, lithium ion polymer batteries, and lithium polymer batteries, according to the type of electrolyte used therein.
Demand for thin prism or pouch type batteries has increased as the size of mobile devices has decreased, and particularly, pouch type batteries are noteworthy, as pouch type batteries are relatively light and can be easily deformed to have desired shapes and be manufactured at low cost.
Recent mobile devices are relatively small and have various shapes. Due to these technical trends, batteries in which the same battery unit cells are stacked may be unsuitable for such mobile devices because it may be difficult to match the shapes of such batteries and mobile devices without any dead space therein. Therefore, it is necessary to develop batteries having various shapes for mobile devices.
Accordingly, there is increasing demand for batteries having stepped shapes. If batteries are shaped (stepped) according to the shapes of devices in which the batteries will be accommodated, dead space can be minimized to efficiently use the interior space of devices. In other words, the capacity of batteries can be increased by designing the batteries having stepped shapes.
That is, it is necessary to develop electrode assemblies and batteries that have high degrees of capacitance and can be variously shaped according to the shapes of devices to which the batteries will be attached.
An aspect of the present invention provides an electrode assembly having satisfactory electric capacity characteristics, a slim shape, and structural merits, to allow for the realization of various designs.
Aspects of the present invention also provide a battery cell, a battery pack, and a device including the electrode assembly.